Firebox and Fireware OS
CVE-2026-81433: Fireware OS Pre-Authentication Stack Buffer Overflow in fingerd Allows Remote Code Execution
A stack-based buffer overflow vulnerability in WatchGuard Fireware OS's DHCP fingerprinting daemon (fingerd) allows an unauthenticated attacker with adjacent network access to execute arbitrary code or crash the process by sending a specially crafted DHCP packet.
Published
Automatic summary from the vendor's CVE record. We haven't written a full analysis of this vulnerability yet.
Affected and fixed versions
| Product / branch | Fixed in |
|---|---|
| Fireware OS (Default) 2026.3 | 2026.3.2 or later |
| Fireware OS (Default) 2025.0 | 2026.2.3 or later |
| Fireware OS (Default) 12.0 | 12.12.3 or later |
Always confirm against the vendor advisory, which lists every fixed hotfix.
What it is
A stack-based buffer overflow vulnerability in WatchGuard Fireware OS's DHCP fingerprinting daemon (fingerd) allows an unauthenticated attacker with adjacent network access to execute arbitrary code or crash the process by sending a specially crafted DHCP packet.
Exploitation
WatchGuard is not aware of any exploitation of this vulnerability in the wild.
Sources
KEV status, EPSS score and vendor data refreshed automatically, last on 13 Oct 2026.